Traditionalists will attempt to sway the conference behind a proposal to abolish "opt-out" schools, but Mr Blunkett told a fringe meeting Labour had to set an agenda for tomorrow rather than "repeating the rhetoric of yesteryear".
The division over opt-out schools - a key feature of the Government's schools reforms - is likely to surface tonight at a meeting to be addressed by Roy Hattersley, who has accused the leadership of pandering to the middle-class.
Conference managers will oppose the abolition move on the grounds that it is at odds with Labour's policy document Diversity and Excellence.
But Mr Blunkett told GMTV: "Some supporters should remember that there are those of us, including myself, who have been battling away for 30 years on the issue of equality of opportunity in education."
He was committed to "ensuring that comprehensive education actually works for every child, rather than simply being a rhetorical slogan".
On the Labour Leader's decision to send his son to the Oratory School, west London, Mr Blunkett said he thought Mr Blair was "wise to talk with his family about the options that would have been available to him if the Oratory School had remained a voluntary-aided school".
"No one would have blinked an eyelid had he sent his child there a few years ago."
Mr Blunkett said the party's policy on grant-maintained schools conformed with principles already agreed - equity of funding, a fair admissions policy, and a key planning role for local education authorities - and were designed to raise education standards for the majority, not the favoured few.
The commitment to limit class sizes for all children between five and seven, which Mr Blair is expected to announce tomorrow, was a key part of this, Mr Blunkett said.
The pledge is expected to cost up to pounds 36m and could be paid for by phasing out the pounds 110m Assisted Places Scheme, which subsidises independent school places for children of low-income families.
The education spokesman also hinted at a review of the charitable status of independent schools. "We believe that schools like Eton, Prince William being there or anyone else, should not be treated as if they were Oxfam. It is not our job to subsidise private education."
Trailing the themes Mr Blair will set out tomorrow, Mr Blunkett said welfare to work, raising standards in education and moving towards full employment were the core ideas of the modern Labour Party.